This invention relates to a burner adapted to be used on gas flare stacks and the like.
The burner has particular application in cases where low pressure gas flows are to be flared, as from stock tank gas vents. In this type of situation, it is usually necessary to provide some means for drawing the low pressure gas from its source into the combustion zone at a reasonable rate and for mixing it with air to provide a combustible mixture which will burn substantially smokelessly.
From U.S. Pat. No. 3,833,337, issued to D. H. Desty on Sept. 3, 1974, it is known to provide a flare stack burner having the following features:
(a) separate high and low pressure gas lines are provided; PA1 (b) a valve body of the Coanda type is fixed to the end of the high pressure line and cooperates therewith to form a narrow annular outlet through which the high pressure gas flows; PA1 (c) the outlet end of the high pressure line is in the form of a bellows so that the end face of the line moves axially relative to the stationary Coanda valve body to vary the width of the annular outlet and thereby maintain a constant backpressure within the feed line; and PA1 (d) the low pressure gas line extends through the Coanda valve body so that its outlet coincides with the end face of said body, which is immediately adjacent the combustion zone.
In operation, the high pressure gas flows out of its feed line outlet and follows the transverse and curved surface of the Coanda-type valve body which is positioned at said outlet. A low pressure zone is created by this gas flow adjacent the curved surface, with the result that air and low pressure gas are drawn into the high pressure gas flow and mix therewith to form a combustible mixture.
According to my investigations, this prior art burner uses about five parts of high pressure gas for each part of low pressure gas. It is the object of this invention to provide a burner which significantly reduces this ratio.